Method of mechanically manufacturing hollow glass objects



May 18, 1965 P. VAN ZONNEVELD 3,184,297

METHOD 0F MECHANICALLY MANUFACTURING HOLLOW GLASS OBJECTS Filed Jan. 30,1961 4 Sheets-Sheet 1 e w I mm FIG. 3 FIGA F IG.5

INVENT OR P|E TER .VAN ZONNEVELD MAZM;

May 18, 1965 P. VAN ZONNEVELD 3,184,297

METHOD OF MECHANICALLY MANUFACTURING HOLLOW GLASS OBJECTS Filed Jan. 30,1961 4 Sheets-Sheet 2 AG T y 1965 P. VAN ZONNEVELD 3,184,297

METHOD OF MECHANICALLY MANUFACTURING HOLLOW GLASS OBJECTS Filed Jan. 30.1961 4 Sheets-Sheet 3 FIG. 13

FIG. 12

FIG. 11

INVENTOR PIETER -VAN- ZONNEVELD y 1965 P. VAN ZONNEVELD 3,184,297

METHOD OF MECHANICALLY MANUFACTURING HOLLOW GLASS OBJECTS Filed Jan. 30,1961 4 SheetsShjeet 4 FIG. 1B

FIG.19

FIG. 18

INVEOYQNTQR v PIETER VAN ZONNEVELD BY MK AGEN United States Patent 4Claims. Eel. 65-48 This invention relates to a method of mechanicallymanufacturing hollow glass objects, for example, glass bulbs forelectrical incandescent lamps.

in a known method a preformed glass portion, clamped at the top in aholder, is shaped into a parison, of which the lower end moves withrespect to the holder during this formation from a higher level to alower level, the parison being at the same time blown up to obtain ahollow glass object.

In this method the lower end of the parison sags gradually with respectto the holder. By supplying, during sagging, air and/ or heat to theparison, the latter can be acted upon, in general, so that towards theend of the available period for sagging a parison is obtained of whichthe shape and the glass distribution are such that an object of thedesired shape and glass distribution are obtained after blowing. In thecase of a large number of kinds of objects the shape of the final objectgives little rise to difiiculties in the formation of the parison. Thisknown method is suitable to form objects of which the shape is such thatthe ratio between the maximum size at its widened part and the size ofthe narrower part does not exceed a given value. However, if this ratiois chosen higher it is gradually more diflicult in practice to acteffectively, solely by air and/ or heat supply during the sagging of theparison, upon the distribution of the glass mass in the parison so thatat the end of the available period for sagging a parison is obtained ofwhich the shape is such that after blowing the object of the desiredshape and glass distribution can be obtained therefrom.

For each kind of hollow glass object there can be found a maximum ratiobetween the maximum size of the widened part and the size of thenarrower neck part and if this ratio is exceeded it becomes practicallyno longer possible to carry out the known method. This maximum ratio,which also depends upon the length of the object, amounts for examplefor bulbs of electrical incandescent lamps, to about 1.8.

If yet an object in which the said maximum ratio is exceeded is to bemanufactured by the known method, the results will sometimes leave muchto be desired. The object may then, indeed, have the required shape, butat the maximum diameter the wall may be very thin, its thickness beingmostly smaller than is required with respect to the locally desiredmechanical rigidity. On the contrary, the wall thickness at theso-called bottom, i.e., at the place farthest remote from the neckopening, is too large. Such an undesirable ratio between the wallthickness is due to the fact that the suitable glass distributionalready obtained in the glass portion gets lost for the major partduring the sagging and blowing of the parison.

The present invention has for its object to provide measures by whichthe Wall thickness in the parison can be favourably acted upon when thelower end of the parison moves from a higher level to a lower level.

The method according to the invention is characterized in that duringthe formation of the parison a part of the parison co-operates with acatching member movable in a vertical sense with respect to the parisonand con trolled so that the part of the parison co-operating with thiscatching member moves with a sense-reversing, vertical acceleration and,if necessary, with a sense-reversing, vertical speed, while heat may besupplied to the parison. By imparting this varying vertical accelerationto part of the parison during sagging it is possible to subject theparison a few times to a process in which the glass distribution of theparison is changed and adapted to the glass distribution desired at theinstant concerned in sagging. In general, either during this process orafter this process heat is to be supplied to change at the same time theshape of the parison. By carrying out the method according to theinvention the glass mass can be displaced towards that part of theparison which is to have the largest size of the final hollow glassobject, the place Where the parison is in contact with the catchingmember owing to the aforesaid process, which has a bulging effect on theparison.

The part of the parison co-operating with the catching member may be thelower end of this parison, but as an alternative another part may beused to this end. This part may lie between the top end and the bottomend of the parison.

The use of a catching member is known per Se in a method of mechanicallymanufacturing bottles. A movemerit-controlled catching memberco-operates with the lower end of the sagging parison, but this lowerend has, with respect to the remainder of the parison, such a large massthat, in the absence of a catching member, this end sags with anuncontrolled, excessive speed with respect to the holder in which thetop end of the parison is clamped.

In accordance with the shape and the desired glass distribution of thefinal object to be manufactured in accordance with the invention theprogramme of the movements of parison and catching member may vary. Itis a condition, however, that the vertical acceleration of the part ofthe parison co-operating with the catching member should repeatedlychange its direction. Only then is it possible to effect a bulgingaction on the parison. An example of such a movement is that in whichduring the sagging of a parison, a vertically movable catching memberexerts repeatedly a reverberating action on the lower end of theparison. The lower end of the parison thus moves not only with arepeatedly reversing vertical acceleration but also with a reversingvertical speed.

The invention provides furthermore an embodiment of the method describedabove in which the parison rotates about its longitudinal axis and thecatching member performs a rotation about its vertical axis, the angularvelocity of this movement corresponding in size and sense with that ofthe parison. The axes of rotation are in line with each other. Thisembodiment may be employed, for example, if the parison is to be exposedto heat produced by burners directed towards the parison.

The invention provides furthermore a device for carrying out the methoddescribed. This device, which comprises pre-forming members for a glassportion, a holder to clamp the top end of the pre-formed glass portion,a vertically movable catching member and, if necessary a blowing mouldto blow the parison, is characterized in that the control-mechanism ofthe catching member is such that part of the parison co-operating withthe catching member moves with a repeatedly reversing vertical Vbodiment the top side 9 of the invention objects can be manufactured ofwhich the diameter at the widest part is at least twice the smallestneck diameter. They may be used successfully, if the condition is to befulfilled that the diiferences in wall thickness substantiallythroughout .the object should besmall.

The invention may turthenmore be employed to manufac-' this member 5 hasa shape which corresponds to the outer profile of the bottom part of thefinal object. The catching member is movable in a vertical sense (13)and is adapted to rotate about its centre line v16. After thepreliminaryformation and after the removal of the. preliminary mould 3 from theholder 1, this holder is rotated about the vertical axis 16. The angularvelocities of the holder 1 and of the catching member 5 in thisembodiment correspond with each other in size and sense. The rotation ofthe holder with the clamped parison and'of the catching member 5 isutilized in this case to. permit supplying heat to the sagging parisonby means of burners (not shown) directed towards the parison.

While the parison 7 moves from a higher level to a lower level, thelowerend 110 of this parison can copperate with the top side 9 of thecatching member 5 in the son by co-operation with a catching. member,this parison being finally blown up .to obtain a hollow-glass object.

FIGS. 8 and 9 show displacement-time diagrams. FIG. 8 it is indicated bytull lines in what manner, for example, the part of the parisonco-operating with the catching member moves from a higher level to alower 'level with respect to the holder.

catching member is indicated by broken lines. FIG. 9

The path covered by the shows a further example of a path which may becovered by the catching member. a

FIG. 10 shows part'of the holder to clamp the top end of a glass portionor parison.

FIGS. 11 and 12.relate to the formation of a parison, the catchingmember having a central pin movable independently of the catchingmember. The parison shown 'in FIG. 12 has a lower part protruding fromthe bulbshaped portion. FIG. 13 shows the finalobject.

FIGS. 14 and 15 show one embodiment in lwhich the catching member'alsocomprises a rnovable, central pin. The parison shown in FIG. 14 has asunken portion. The final object is shown in FIG. 15.

FIGS. 1-6 to 19 relate to one embodiment in which the final object hasnot only a thickened bottomportion but also a strongly widened,thin-walled bulb portion.

In .the embodiment shown in FIGS; 1 to 7 .for the mechanical manufactureof hollowglass objects by a combined,pressing-blowing process, forexample bulbs for electrical incandescent lamps provision is made of aholder 1 (see also FIG. 10) with a slidable templet 2,

which co-operate with a preliminary form 3 in the ar- 'rangement shownin'FIG. 1. When a glass portion is introduced into the preliminarymould3,. this portion can be to have a maximum diameter d and a minimumdiameter d chosen to be 3 /2. A further condition is that the wallthickness of the final object should be uniform. 7

Already in the prem-iniary formation of the glass portion (FIG. 1) careis taken that a particular shape of this glass portion is obtained,which portion has a thickened part 17 as compared with the further partof the prefor-med portion. This part 17 is to be widened to a muchlarger diameter, .when the parison is blown up into the final object. Tothis end the portion7 (FIG. 2) is deformed by means of suitable parisonformation so that the parison assumed the shape 8 in the blowing mould(FIG; 7). For this parison formation use is madeof a movement-controlledcatching member 5. In this em- In this embodiment the ratio between dand d is manner illustrated in FIGS. 3 to 5; The drawing shows onlythree stages, but this number may, if desired, be increased. I

The catch member 5 is moved by any suitable means 6 (hydraulic,pneumatic, .or mechanical)v in a series of reciprocations of diiferentamplitude such as illustrated in the dash lines of FIG. 8 and describedmore fully in connection with said figure.

The co-operation between the lower end of the parison supplied. Thecatching member 5, of which the controlled movement is indicated in thisfigure diagrammatL cally by broken lines, performsaway from 33' anupward movement .35. At 36 the top side of this catching member exertsan upward push on the parison so thatthe lower end of the parison alsoperforms an upward moveinent and arrives at a higher level (37),, whereit is held fora short time. Thus the parison is subjected to a bulgingaction. By'supplying a small amount of ,air toxthe linterior'of theparison, the latter will be blown up slightly, so that the widened shapeof FIG. 3 is obtained. Then the catching member is rapidly moveddownwards as ind-icated by 318 .v Thus the lower end of the parison cansag freely along the curve 39'with respect to the holder'l.

However, this movementisinterrup-ted bythe, upward movement of the.catching member asindicated by 40. The place where the contact isestablished is designated by 41. Consequently, the lower end of theparison is glass mass is displaced, where theparison is in contact withthe catching member," in a direction of that part of the parison whichhas the maximum diameter d in the final glass object" Thepart 17 of theportion 4 (FIG. 1) assumes a gradually larger diameter in the subsequentsuccessive stages of the process and the, thickness of this part 17diminishes'gradually (17, 7, 21, 22, 23, 24). The part 19 of the parisonnear the. clamping place 18 (FIG. 4) is substantially not widened whenair is supplied, since as soon as the parison starts sagging, this parthas a smaller wall thickness. Consequently, the part -19 cools morestrongly than the further parts of the parison,.so that it becomes lessreadily deformable.

The lower end of the parison, which arrives from a higher level to alower level with a repeatedly reversing acceleration, is set freeseveral times from the catching member during the sagging process. Itwill be seen from the further description (FIGS. 16 to 19) that it isalso possible to maintain the contact between the lower end of theparison and the catching member during sagging.

In the embodiment described the lower end of the parison contacts eachtime the top side 9 of the catching member 5, when the latter movesupwards (35, 40). In accordance with the shape of the final object thiscontact may be established at a different instant. From the point 29 ofFIG. 8 onwards other curves 26, 27 and 28, 29 of the movement of thelower end of the parison with respect to the holder 1 may be chosen.

The successive supplies of small amounts of air to the interior of theparison to widen this parison at least partly, also termed puffing,occur in accordance with the foregoing when the lower end of the parisonis held at a constant level for a short time (37, 42). In accordancewith the final shape of the object the puffing instants may be chosendiflerently, i.e., sooner or later. It may even be desirable with a viewto the desired degree of bulging to change the control of the catchingmember. This is illus trated in FIG. 9. The displacement-time diagram ofthis figure for the top side 9 of the catching member 5 initially hasthe same course (51, 52) as the diagram of FIG. 8; consequently, thelower end of the parison is similarly subjected to a few bulging actionsexerted by the catching member. At the instant t the catching memberperforms an upward movement 53 so that the lower end of the parisonarrives at a greater distance from the starting point 33 than during thefirst upward movement 54. When the catching member arrives at the level55, a longer or a more vigorous air supply will widen further thediameter of the parison. After the lower end of the parison has saggedfurther in a similar manner as at 51 and 52., the same process may berepeated at 56. Also in this embodiment the lower end of the parisonmoves with a repeatedly reversing acceleration and, as the case may bewith a reversing speed.

FIG. illustrates the structure of the holder 1 employed. The holdercomprises a sleeve 58, in which a further sleeve 62 is arranged. In thesleeve 62 a templet 59 is adapted to move. Provision is furthermore madeof a plurality of claws 61, connected with resilient strips 69 andforming together a closed ring in the' closed position shown. In theopened position of these claws 61a this is not the case. The top end ofthe parison clamped in the holder is designated by 65. The sleeve 62 isfurthermore provided with a plurality of axial recesses 63. In theposition shown of the templet 59 air may be supplied in the direction ofthe arrow 68 to the lower side of the templet to transfer the air to theinterior of a parison clamped in the holder. When the final object isobtained and the mould parts 11 and 12 are removed, the blown object canbe removed by lowering the templet 59 in the sleeve 62. The part 67 ofthis templet exerts a pressure on the edge 69 of the object clamped inthe holder. This pressure propagates through the material 65 of theobject to the oblique edge 74 of the claws 61 forming the ring. Thus theclaws 61 are urged aside into the position 61a against the spring actionof the resilient strips 6%). After an adequate displacement of theseclaws the object can be urged downwards out of the holder 1 by means ofthe templet 59. Since in the method described above hot glass is incontact with parts of the preliminary mould, of the catching member andof the blowing mould, the temperature of these parts should not riseconsiderably. This may be achieved by providing the parts with watercooling. Since water cooling is generally known, it will not bedescribed further.

The part of the parison co-operating with the catching member need notalways be the lower end thereof; this part may lie at a different placeof the parison.

If, for example, the object shown in FIG. 13 is to be manufactured, fromwhich, for example, by severing the parts 70 and '71, an object of alength a open at both ends can be obtained, use may be made of acomposite catching member as shown in FIG. 11. This catching membercomprises an annular part '72, which can be governed in a verticalsense. A pin 73 is vertically movable in the centre of this member. Thiscombined catching member may be employed as follows. In the mannerdescribed above such a bulging effect is exerted on the lower end of theparison, while the pin 73 occupies the position shown, that this parisonassumes a slightly widened shape as is shown in FIG. 11. Then the pin 73is moved so that it moves downwards with respect to the ring 72. Whensubsequently the ring 72 exerts successively a few upward shocks on theparison 76, the bottom part '77 of this parison can sag into the annularpart 72. Then this bottom part will assume the shape designated in FIG.12 by 78. It appears that in this manner objects as shown in FIG. 13 canbe manufactured, which have a strongly widened, spherical part and aprotuberance, while the wall thickness is very uniform.

In the embodiment shown in FIGS. 14 and 15 the pin 86 is also moved withrespect to the annular catching member 82 after the parison has beenprovided a slightly widened part as shown in FIG. 11. The direction ofmovement with respect to the annular catching member 82 is, however,reversed. As a result thereof the parison can be provided with a sunkenpart 83. The final object (FIG. 15), as well as the object shown in FIG.13, is manufactured by arranging blowing mould parts around the parisonafter the last bulging action.

In the embodiment shown in FIGS. 16 to 19 for the manufacture of ahollow glass object of which the widened part corresponds to the shapeof the mould cavity 84 and the bottom part is to be shaped in the form87, a bottom part M and a part with a partly thickened, upright sidewall 93 are formed already during the preliminary formation of the glassportion. The shape of the bottom part 91 is such that it correspondssubstantially with the shape of the bottom 87 of the final object. Thecatching member 95 forms part of the preliminary mould with the parts 96and 97 and of the blowing mould with the parts and 86. After the glassportion has been preshaped as is shown in FIG. 16 and the templet 98 hasbeen moved upwards and the preliminary mould parts 96, 97 have beenremoved, this glass portion, clamped at its top in the holder 1, canarrive from a higher level at a lower level, while, if desired, heat issupplied, when the catching member 5 performs a downward movement.During this downward movement the parison remains at its lower endconstantly in contact with the top side of the catching member. Thusduring sagging at least the outer shape of the bottom part is preventedfrom being deformed. By imparting to the catching member in the mannerdescribed above a repeatedly sense-reversing acceleration and, ifnecessary, a sense-reversing vertical speed and by introducing air intothe parison in the intervals, the parison will also in this embodimenthave finally a strongly widened part (FIG. 18). Of the various stagesbetween the preliminary formation of the glass portion (FIG. 16) and theblowing of the parison 99 in the blowing mould, only two stages (FIGS.17, 18) are shown in the drawing. Thus cup-shaped objects can bemanufactured, in which at least at the widest part of the object thewall thickness is comparatively small and the bottom part has acomparatively strong wall thickness.

What is claimed is:

1. A method of manufacturing hollow glass objects comprising the steps,engaging one end of a pre-shaped glass body, supporting said body whileelongating the other end by subsidence to form a parison, contactingsequentially the other end of said parison in a direction opposite thedirection of subsidence and of different amplitudes to change the glassdistribution in the parison, and puffing the parison into a hollow glassobject having a substantially uniform wall thickness.

2. A method of manufacturing hollow glass objects comprising the steps,engaging one end of a pre-shaped glass body, supporting said body whileelongating the 7 other end by subsidence to form a parison, contactingsaid other end of the parison with sequential upward vertical movementsof difierent amplitudes to change the glass distribution .in the.parison, and puffing the parison into a hollow glass object havinga'substantially uniform Wall thickness. and blow moulding said objectinto a finished shape.

3. A method of manufacturing hollow glass objects comprising the steps,engaging one end of a pre-shaped glass body, supporting said bodywhilefelongating the other end by subsidence to form a parison,'rotatingand heating the parison while it is beingformed, contacting thesubsiding end of the parison with sequential upward vertical movementsof diiferent amplitudes to change the glass distribution in the parison,and pulling the parison into a hollow glass object.

4. A method of manufacturing hollow glass objects comprising the steps,engaging one end of a pre-shaped glass body, supporting said body Whileelongating the other end by subsidence, to form a parison, rotating.said parison at a given angular velocity and heating the parison,contacting the subsiding end ofthe parison with puffing the parison intoa hollow glass object having ,a

substantially uniform wall thickness and blow moulding said object intoafinishedshape.

References Cited by the Examiner UNITED STATES PATENTS Proeger' 65261Sievert L 6563 Bryce L 65242 Rau Wood .Q. 6579 Bartlett 6580 Roirant6582 Sehutz 65261 X Howard 6575 Schlitz 65212 Soubier -L- 65263 X Gordon65-79 Dichter 65242 X Kopitke 26496 Laidig 65229 McLaughlin 6564 Bailey65 -261 X I Stutske et a1 -3 '6570 Eastus et a1 65,-166

FOREIGN PATENTS Great Britain.

' Germany.

' DONALL H/SYLVESTER, Primary Examiner.

ARTHUR P. KENT, Examiner.

1. A METHOD OF MANUFACTURING HOLLOW GLASS OBJECTS COMPRISING THE STEPS,ENGAGING ONE END OF A PRE-SHAPED GLASS BODY, SUPPORTING SAID BODY WHILEELONGATING THE OTHER END BY SUBSIDENCE TO FORM A PARISON, CONTACTINGSEQUENTIALLY THE OTHER END OF SAID PARISON IN A DIRECTION OPPOSITE THEDIRECTION OF SUBSIDENCE AND OF DIFFERENT AMPLITUDES TO CHANGE THE GLASSDISTRIBUTION IN THE PARISON, AND PUFFING THE PARISON INTO A HOLLOW GLASSOBJECT HAVING A SUBSTANTIALLY UNIFORM WALL THICKNESS.